In recent years, MOSFETs, such as a super junction MOSFET, highly efficient with a low on-resistance have been developed. Moreover, conventionally, there has been proposed a power converter for driving an inductive load, the power converter using an MOSFET as a switching element provided in an inverter circuit inside the power converter (see Japanese Patent Application Publication No. Hei 10-327585, and hereinafter, referred to as the “official gazette” as needed).
In the power converter in this proposal, reverse voltage application circuits are each provided to reduce a loss caused by a reverse current that is generated, according to the ON/OFF of a MOSFET serving as a switching element, in a parasitic diode (a diode naturally created on a circuit due to the structure of the MOSFET) connected in antiparallel with the MOSFET. Namely, when one of the MOSFETs changes from ON to OFF, this reverse voltage application circuit applies a reverse voltage to the parasitic diode before the ON timing of the other FET that is paired with the former MOSFET. The applied reverse voltage is based on a drive signal generated by combining a PWM (Pulse Width Modulation) basic signal with an OFF signal of the MOSFET from which the reverse voltage is applied, the PWM basic signal being generated by comparing a triangular waveform signal with a reference signal, the reference signal being based on a reference frequency and a reference voltage.